This invention relates to automatic test systems, and more particularly, to interface adapters for automatic test systems that allow test boards designed for one test system to be used on different test systems.
Automatic test systems are used by manufacturers of electronic devices such as voltage regulators, radio frequency circuit devices and other circuits, to test the devices before they are installed in an end product. The test systems can be configured to test a variety of devices under various test conditions, using a test head that has as many as 3,000 or more electrical terminals for connecting to and testing one or more devices under test (DUTs).
DUTs can be tested in an unpackaged condition on a semiconductor wafer, or in a packaged condition with leads attached and perhaps encapsulation completed. To test the packaged DUTs, a special board known as a DUT board is constructed. The board is especially designed to hold one or more DUTs, and to be easily installed on the test head. The board connects terminals or leads on the DUT(s) to the terminals in the test head. In this manner, one test system can be used for different devices, by designing a DUT board for each device.
Unpackaged DUTs are tested using a probe card that makes electrical contact with at least selected devices on the wafer. A probe interface ring connects a prober interface board (similar to a DUT board) to the probe card. The probe interface board and probe card are uniquely designed for testing a particular device on a particular test system.
Different test systems have different test heads to which DUT boards are secured, so DUT boards made for one test system usually cannot be used on a different test system, because the DUT boards do not fit the test head of the other test system. This limits the flexibility of a user having several test systems with different test heads, and can lower productivity. This is also a problem for users who want to purchase test systems having different test heads, particularly less expensive, smaller or better test systems, because new DUT boards must be made for each device, which is time-consuming, requires engineering resources, and is expensive.
Accordingly, one object of this invention is to provide new and improved interface adapters for automatic test systems.
Another object is to provide new and improved interface adapters for automatic test systems that allow DUT boards designed for one test system to be used on other test systems.
In keeping with one aspect of this invention, a removable interface adapter for automatic test systems having a test head includes a first set of contacts configured for electrical connection to first contacts in the test head, and a second set of contacts configured for electrical connection to a test board that includes or provides an interface to one or more devices to be tested. The first and second contacts are interconnected so that devices used with the test board can be tested through the test head. The interface adapter can be easily removed, however, for testing using DUT boards having different contact configurations.